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Symptoms and Signs of What Is Psoriasis?

Doctor's Notes on What Is Psoriasis?

Psoriasis is a chronic autoimmune skin disorder that causes patchy, red, scaly areas of skin. It typically affects the arms, legs, trunk, scalp, knees, elbows, and lower back but it may occur on any part of the skin. The most common form of psoriasis is called plaque psoriasis (psoriasis vulgaris).

Symptoms of plaque psoriasis include plaques that are red, raised, scaly skin affecting the scalp, elbows, and knees. The plaques may itch or burn. Flares (periods when the condition worsens) may last weeks to months. Plaques may split and bleed, especially when they occur over joints or on the palms or feet. Plaques may be surrounded by a halo or ring of blanched skin (Ring of Woronoff). Skin scales are silvery white and thickness varies. Other symptoms of psoriasis include nail changes such as discoloration and separation from the nail bed at the fingertip. In children, symptoms of plaque psoriasis may appear different. Plaques are not as thick and the affected skin is less scaly. Psoriasis often appears in the diaper region in infancy and in flexural areas (underarms, groin, perianal area) and the face in children.

Medical Author: John P. Cunha, DO, FACOEP
Medically Reviewed on 3/11/2019


Kasper, D.L., et al., eds. Harrison's Principles of Internal Medicine, 19th Ed. United States: McGraw-Hill Education, 2015.